TechBook: EMC Compatibility Features for IBM Copy Services on z/OS

EMC® Compatibility Features for
IBM Copy Services on z/OS

Version 1.0

• Compatible Peer (PPRC)
• Compatible Extended (XRC)
• Compatible Native Flash (FlashCopy)

Dean Smith

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Part number H11173

2 EMC Compatibility Features for IBM Copy Services on z/OS TechBook

Contents

Preface

Chapter 1 Introduction
Overview.............................................................................................. 22
Assumptions........................................................................................ 24
Terminology......................................................................................... 25
GDPS deployment .............................................................................. 26
Compatibility....................................................................................... 27
Enginuity features............................................................................... 28
Compatible copy services technologies........................................... 29
GDPS ..............................................................................................29
Compatibility features .................................................................30
Valid combinations for compatibility features .............................. 31

Chapter 2 GDPS Business Continuity Solutions
GDPS overview ................................................................................... 34
GDPS/PPRC........................................................................................ 35
GDPS/HM ........................................................................................... 37
GDPS/XRC .......................................................................................... 38
GDPS/MzGM...................................................................................... 39
Unsupported GDPS architectures .................................................... 40
Common features of GDPS versions................................................ 41
NetView and system automation for z/OS components .......41
NetView operator .........................................................................41
SCRIPT language with TAKEOVER, CONTROL, and
BATCH scripts ............................................................................42
GEOPARM and GEOXPARM storage policy definitions ......43
Policy Data Base (PDB) ................................................................43
Sysplex ...........................................................................................43

EMC Compatibility Features for IBM Copy Services on z/OS TechBook 3

Contents

K systems.......................................................................................44
Documentation.................................................................................... 45
Advanced Copy Services ............................................................45
GDPS manuals ..............................................................................45

Chapter 3 EMC Compatible Peer (PPRC)
PPRC overview ................................................................................... 48
PPRC components .............................................................................. 49
SRDF/S operations and Compatible Peer ...................................... 51
External manifestation of the SRDF/S GROUP name ...........51
Supported and non-supported PPRC modes ................................. 52
PPRC operation................................................................................... 53
Supported PPRC features .................................................................. 57
Metro Mirror and Global Copy ..................................................57
PPRC Consistency Group ...........................................................57
CRIT(Y) ..........................................................................................59
PPRC/FlashCopy Consistency Group Timeout ......................59
Volume pairs.................................................................................60
PPRC pathing................................................................................60
Dependent write consistency .....................................................63
CGROUP FREEZE/RUN and the preservation of
dependent write consistency ...................................................64
Failover Failback (FO/FB) ..........................................................64
Link failure warning ....................................................................65
MIDAW and PPRC ......................................................................65
Query storage subsystem status.................................................65
Summary event notification for PPRC suspends ....................66
Storage controller health message .............................................67
CQUERY LINKINFO...................................................................67
PPRC TSO commands........................................................................ 68
Other PPRC interfaces........................................................................ 69
Compatible Peer versus SRDF/S and Adaptive Copy.................. 70
FAST and Compatible Peer ............................................................... 70
Compatible Peer limitations.............................................................. 70
Designing the solution for z/OS ...................................................... 71
PPRC Symmetrix system configuration specifications...........71
Volume Map PARMs...................................................................72
PPRC connectivity........................................................................72
Security authorization .................................................................73
EMC PPRC link definition ..........................................................73
Conversion from SRDF/S to PPRC emulation............................... 74


Contents

Chapter 4 GDPS/PPRC
GDPS/PPRC and GDPS/HyperSwap Manager (GDPS/HM) ... 76
GDPS/PPRC components ............................................................... 77
EMC DASD Support Matrix for GDPS/PPRC .............................. 81
GDPS/PPRC storage management functions................................ 82
GEOPARM .......................................................................................... 83
Autonomic policies and GEOPLEX................................................. 84
GEOPLEX options PRIMARYFAILURE .................................. 84
GEOPLEX options PPRCFAILURE........................................... 85
Policy implications and remote copy definition ..................... 86
FREEZE autonomic operation.......................................................... 88
Planned FREEZE.......................................................................... 88
GDPS/PPRC DASD script keywords....................................... 89
Sharing VMAX DASD subsystems.................................................. 90
HyperSwap autonomic operations (unplanned HyperSwap) .... 91
Requirements................................................................................ 91
GDPS with HyperSwap architecture ........................................ 93
Planned HyperSwap ................................................................... 96
HyperSwap RESYNCH............................................................... 97
HyperSwap SUSPEND ............................................................... 97
HyperSwap TERMINATE.......................................................... 97
GDPS/PPRC DASD SWITCH HYPERSWAP SCRIPT
keyword ........................................................................................ 97
GDPS/HM HYPERSW commands for HyperSwap and
recovery operations ..................................................................... 98
FAST and HyperSwap ................................................................ 98
GDPS/PPRC DASD subsystem components ................................ 99
HCD definition with GDPS/PPRC ........................................... 99
GDPS K system LOCAL DASD resource................................. 99
GDPS/PPRC utility device....................................................... 100
LCU design ................................................................................. 100
GDPS/PPRC GEOPARM specification......................................... 102
GEOPARM specifications unique to Symmetrix systems ... 102
GEOPARM coding .................................................................... 103
GEOPLEX links .......................................................................... 104
GEOPLEX MIRROR .................................................................. 105
GEOPLEX NONSHARE ........................................................... 106
Activation of a new GEOPARM (CONFIG) .......................... 107
FlashCopy with GDPS/PPRC ........................................................ 108
Justification ................................................................................. 108
Definition .................................................................................... 109
Operation .................................................................................... 109
With HyperSwap deployments ............................................... 110


Contents

Symmetrix systems compatible feature licensing in
GDPS/PPRC .................................................................................. 111
CFHINT considerations................................................................... 112
GDPS/PPRC operations .................................................................. 113
GDPS/PPRC mechanisms ........................................................113
Panel operations (GDPS operator)...........................................114
GDPS/PPRC DASD BATCH SCRIPT VPCEXIT2........................ 115
Locating PPRC error messages within GDPS/PPRC.................. 116
Search NetView’s log for messages .........................................116
Issuing MVS system commands from NetView....................116
Help ..............................................................................................116
GDPS/PPRC employment of alternate subchannel support
with Symmetrix systems................................................................ 117
Validating GDPS autonomic operations........................................ 118
Unplanned FREEZE ...................................................................118
Unplanned HyperSwap.............................................................119
GDPS/PPRC networking topologies............................................. 120
EMC’s role ...................................................................................120
GDPS topologies.........................................................................121
Link budget .................................................................................121
GDPS/PPRC BCRS ....................................................................122
GDPS/PPRC FREEZE and GO/STOP ....................................124
GDPS/PPRC with HyperSwap ................................................126

Chapter 5 Compatible Extended (XRC)
Compatible Extended (XRC) overview ......................................... 130
Features and components .........................................................130
XRC components .............................................................................. 132
XRC planning overview checklist .................................................. 136
XRC operations ................................................................................. 138
XRC operations overview .........................................................138
Remote copy data flow ..............................................................139
SDM Remote copy operations ..................................................140
XRC Copy operations ................................................................140
XRC MONITOR I/O..................................................................141
XRC XADVANCE and XRECOVER operations....................141
Host time-stamping requirements ................................................. 143
Description of XRC components .................................................... 144
Symmetrix SIDEFILE .................................................................144
Sidefile resource management .................................................145
READERTIMEOUT value .........................................................147
Volume pairs...............................................................................148
Utility device ...............................................................................148


Contents

SCSESSION and readers........................................................... 149
Multi-readers .............................................................................. 150
Copy operations......................................................................... 151
System Data Mover (SDM) address space ............................. 152
SDM buffers and memory requirements ............................... 154
System zResources..................................................................... 155
z/OS SDM systems.................................................................... 155
SDM sizing.................................................................................. 156
SDM scalability .......................................................................... 156
XRC parameters ......................................................................... 159
XRC PARMLIB hierarchy ......................................................... 168
XRC control data sets ................................................................ 169
XRC TSO commands ....................................................................... 172
Ordering XRC MC features for XRC implementations .............. 174
Designing an EMC XRC solution for z/OS.................................. 175
Implementation.......................................................................... 175
Sidefile specification.................................................................. 178
Symmetrix configuration file specifications .......................... 178
Linkage and channel extension connectivity......................... 179
FICON linkage requirements................................................... 180
XRC exploitation of PAVs ........................................................ 181
Diagnostics: MODIFY ANTAS000 commands ............................ 183
XRC Performance Monitor (XPM) ................................................ 185

Chapter 6 GDPS/XRC
GDPS/XRC overview...................................................................... 188
GDPS/XRC features and operations ...................................... 188
GDPS/XRC components .......................................................... 188
GDPS/XRC systems and DASD components ............................. 194
Production systems/production sysplexs ............................. 194
GDPS/XRC sysplex................................................................... 194
GDPS/XRC DASD..................................................................... 195
GDPS/XRC GEOPARM mirroring defined ................................. 198
Locating XRC error messages with GDPS/XRC ......................... 199
Locating XRC XRECOVER report ................................................. 200
NetView operations ......................................................................... 201
Getting to GDPS from NetView operator console................ 201
Browse NetView’s log............................................................... 201
Search NetView’s log for messages......................................... 201
Issuing MVS System Commands from NetView.................. 201


Contents

Chapter 7 Three-Site Solution GDPS/MzGM
GDPS/MzGM overview.................................................................. 204
MzGM architecture........................................................................... 206
Terminology in GDPS MzGM......................................................... 212
Symmetrix system compatible feature licensing in GDPS
MzGM.............................................................................................. 213
GDPS MzGM and XRC incremental resynchronization ............. 214
Incremental resynchronization feature ...................................214
Managing incremental resynchronization XRC sessions ....214

Chapter 8 Compatible Native Flash for Mainframe
Compatible Native Flash for Mainframe overview..................... 218
Description of operation .................................................................. 219
Departures from IBM’s solution ..................................................... 220
Supported FlashCopy functions...............................................220
Symmetrix split considerations ................................................220
FlashCopy components ................................................................... 221
Source volume ............................................................................221
Target volume.............................................................................221
FlashCopy session ......................................................................221
FlashCopy modes of operation....................................................... 222
FlashCopy COPY........................................................................222
FlashCopy NOCOPY .................................................................223
FlashCopy INCREMENTAL.....................................................223
FlashCopy TSO commands............................................................. 224
Symmetrix system configuration file settings ............................. 225
Designing FlashCopy solutions for GDPS/XRC deployment ... 226
Traditional DR testing without Zero Suspend FlashCopy...226
Recovery for actual DR..............................................................227
Additional FlashCopy considerations ....................................228
FlashCopy and XRC performance concerns during DR
testing........................................................................................229

Appendix A PPRC PATHing and Linkage Address
Link parameters ................................................................................ 232
Link parameters..........................................................................232
Defining PPRC PATHs with ICKDSF .....................................234


Contents

Appendix B EMC’s Role as a GDPS Storage Vendor
New GDPS deployment.................................................................. 236
Supplementing an existing GDPS implementation ................... 238

Appendix C Sample GEOPARM (GEOXPARM)
Overview ........................................................................................... 240
GDPS/PPRC GEOPARM................................................................ 241

Appendix D GDPS/PPRC Support Matrix
Support matrix ................................................................................. 246

Index


Contents


Figures

1 PPRC components............................................................................................ 49
2 Abbreviated PPRC states ................................................................................ 56
3 GDPS/PPRC components............................................................................... 77
4 GDPS with HyperSwap architecture and DASD connectivity
example............................................................................................................... 93
5 Batch TMP to trigger an unplanned GDPS/PPRC FREEZE.................... 119
6 GDPS/PPRC BCRS architecture .................................................................. 123
7 GDPS/PPRC FREEZE STOP/GO network provisioning with
DWDM.............................................................................................................. 125
8 GDPS/PPRC with HyperSwap network .................................................... 127
9 XRC components ............................................................................................ 132
10 GDPS/XRC components ............................................................................... 189
11 GDPS/MzGM architectural components ................................................... 206


Figures


Tables

1 Allowable Compatible Extended copy combinations ..................................31
2 Query DASD storage controller status comparison .....................................66
3 PPRC TSO commands ......................................................................................68
4 Symmetrix configuration settings for PPRC compatibility .........................71
5 Symmetrix configuration SRDF settings for PPRC compatibility ..............72
6 EMC features for GDPS/PPRC implementation ........................................111
7 Feature requirements and compatibility features ......................................136
8 XRC PARMLIB recommendations ................................................................161
9 XRC commands ...............................................................................................172
10 MC products for XRC implementation ........................................................174
11 PAV enablement ..............................................................................................181
12 ANTAS000 command functions ...................................................................183
13 MC features for GDPS MzGM implementation .........................................213
14 FlashCopy commands ...................................................................................224
15 Symmetrix PPRC link parameter director map hex lookup .....................233
16 Support Matrix .................................................................................................246


Tables


Preface

This TechBook is intended as an introduction to EMC’s compatibility
features for IBM’s Advanced Copy Services technologies. Its primary
function is to provide EMC personnel and customers in pre-sales or early
implementation activities a quick guide to the configuration and operations
of PPRC, XRC, and FlashCopy compatibility features as they are supported
by EMC. In addition, overview of common deployments of the Advanced
Copy Services features and the degree of EMC’s compliance with those
features is provided, noting when relevant departures in compatibility occur.
This TechBook provides the reader with functional insight into EMC’s role
in the deployment and operations of GDPS.
As part of an effort to improve and enhance the performance and capabilities
of its product lines, EMC periodically releases revisions of its hardware and
software. Therefore, some functions described in this document may not be
supported by all versions of the software or hardware currently in use. For
the most up-to-date information on product features, refer to your product
release notes. If a product does not function properly or does not function as
described in this document, contact your EMC representative.

Audience This TechBook assumes some familiarity with the Symmetrix line of
storage systems and EMC’s native remote copy technology. It is the
intention of this manual to document the methodology of a remote
copy implementation with EMC’s compatible copy services
microcode features: pre-sales, customer consulting, GDPS
implementation, and initial problem determination aid. The materials
within do not assume that Symmetrix features will be employed in a
systems managed solution (such as GDPS).


Preface

Related For EMC documentation, refer to EMC Online Support at
documentation https://support.emc.com, search by product, and choose
Documentation.
◆ EMC Symmetrix VMAX and DMX Series Software Ordering
Information and Configuration Guidelines
◆ EMC Mainframe Technology Overview
◆ EMC Symmetrix Product Guide
◆ EMC SRDF Product Guide
◆ DFSMS Extended Remote Copy Reference Information for Advanced
Users
◆ DFSMS Advanced Copy Services
◆ GDPS/PPRC Installation and Customization Guide
◆ GDPS/HM Installation and Customization Guide
◆ GDPS/XRC Installation and Customization Guide
◆ GDPS/MzGM Planning and Implementation Guide
◆ NetView and SA for z/OS manual recommendations
For IBM documentation, refer to the IBM website at
http://www.ibm.com.

Note: All GDPS installation and customization guides are IBM-licensed
materials and are available for use at the customer's site by the customer, the
customer's contractors, and the customer's vendors once a GDPS licensing
agreement is signed by the customer.

Author of this Dean Smith is a Consulting Software Engineer in EMC's z/OS
TechBook Automation Team. Prior to rejoining EMC, Dean worked for IBM
USA and IBM China and has extensive experience implementing
business continuity solutions worldwide for many of the largest
z/OS implementations, including the first GDPS implementations in
the USA, Canada, China Mainland, Taiwan, Malaysia, and India.
In addition to assisting in consulting aspects of GDDR
implementations, Dean has collaborated on the development of EMC
Compatibility Microcode features and assisted in the implementation
with GDPS deployments.
Dean is a contributing author for several EMC GDDR publications.


Preface

The author would like to thank the following EMC employees for the
significant contributions they made to the writing of this TechBook.
Without them, this TechBook would not have been possible.
Brett Quinn, Bill Thibodeau, Carol Saparnis, Betsy Patapoutian,
Eskandar (Esy) Lavi, Carsten Hansen, Barry Matthews, Mary Nevin,
and Daniel Murphy.

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Preface

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Preface


1

Introduction

This chapter provides information on what is included in this
TechBook, compatibility microcode features, and remote copy
technologies:
◆ Overview ............................................................................................. 22
◆ Assumptions ....................................................................................... 24
◆ Terminology ........................................................................................ 25
◆ GDPS deployment ............................................................................. 26
◆ Compatibility...................................................................................... 27
◆ Enginuity features.............................................................................. 28
◆ Compatible copy services technologies .......................................... 29
◆ Valid combinations for compatibility features .............................. 31

Introduction 21

Introduction

Overview
This Techbook is intended as an introduction to EMC® compatibility
features for IBM’s Advanced Copy Services technologies.
Its primary function is to provide EMC personnel and customers in
pre-sales or early implementation activities a quick guide to the
configuration and operations of PPRC, XRC, and FlashCopy
compatibility features as they are supported by EMC.
In addition, this TechBook provides an overview of common
deployments of the Advanced Copy Services features and the degree
of EMC’s compliance with those features noting, when relevant,
departures in compatibility occur.
Advanced Copy Services features include:
◆ PPRC
◆ XRC
◆ FlashCopy
An overview of how those features are commonly integrated into the
GDPS (Geographically Dispersed Parallel Sysplex) management
software offerings, including:
◆ GDPS/PPRC
◆ GDPS/HM
◆ GDPS/XRC
◆ GDPS/MzGM
This TechBook distinguishes channel compatibility (to which EMC is
100% compatible, such as FICON, MIDAW, zHPF, etc.), with copy
services compatibility (to which EMC is selective), based on customer
demand, perceived value, etc. This TechBook also notes which copy
services options are not supported.
Intentions for this publication include:
◆ Feature ordering
◆ Diagnostic interfaces unique to EMC Symmetrix® VMAX® family
arrays
◆ Configuration and operations of the compatibility features
◆ Support levels in EMC Enginuity™


Introduction

◆ Validated z/OS release levels
◆ Functional overview of the compatibility features as commonly
deployed
◆ Overview of GDPS operations and initial problem determination
aid
◆ EMC Symmetrix Remote Data Facility (SRDF®) to PPRC
conversion

Overview 23

Introduction

Assumptions
This Techbook assumes some familiarity with the Symmetrix line of
storage systems and EMC’s native remote copy technology.
It is the intention of this TechBook to document the methodology of a
remote copy implementation with the following EMC compatible
copy services microcode features:
◆ Pre-sales
◆ Customer consulting
◆ GDPS implementation
◆ Initial problem determination aid
The materials within do not assume that Symmetrix features will be
employed in a systems managed solution (such as GDPS).
Consequently, the native remote copy technologies are discussed in
separate sections from their possible GPDS deployment
considerations.


Introduction

Terminology
Throughout this manual the terms PPRC, XRC, and FlashCopy are
used generically when they apply to both the EMC and IBM
offerings.
Additionally, within EMC’s nomenclature the terms mirroring and
remote copy have very distinct meanings and are not synonymous. The
IBM usage for these terms is frequently synonymous1. This is
especially true in the context of GDPS remote copy operations and
the status of volume pairs. Traditionally, EMC employs "mirroring" as
it relates to device-level mirror positions, a concept within the
Symmetrix architecture, which may or may not be an SRDF
relationship.

1. The rebranding of the different modes of PPRC and XRC are case-in-
point. Metro Mirror is PPRC synchronous; Global Mirror is a hardware
composition of PPRC and FlashCopy; Global Copy is PPRC/XD; and
z/Global Mirror is XRC.

Terminology 25

Introduction

GDPS deployment
One of the intentions of this manual is to provide the reader with
functional insight into EMC’s role in GDPS deployment and
operations. Recognizing that as the Direct Access Storage Device
(DASD) vendor we are in competition with organizations (within
IBM and other DASD vendors), but not necessarily with the
organizations responsible for the marketing, support, and
implementation of GDPS.
The aim is to provide the reader with an enhanced degree of
competency on GDPS implementations so as to provide additional
assurance of EMC’s support and competency in the GDPS market
place. Moreover, since much of the GDPS implementation
information is licensed to the implementation site, this manual
intends to provide EMC employees and EMC’s customers with
information critical to GDPS planning and implementation with
EMC’s products.
To that end, this document focuses on topics of storage
implementation and remote copy operations, but refrains from topics
related to GDPS software installation, as well as GDPS z/OS systems
implementations, which are otherwise quite adequately documented
in their appropriate GDPS product guides.


Introduction

Compatibility
In addition to this TechBook’s objective of improving technical
implementation competency, another intention is to improve the
understanding of EMC compatible extended copy features and
Symmetrix DASD in competition with other storage vendors in the
GDPS market place.
This TechBook makes an effort to distinguish the different GDPS
products and identify not only the requisite storage deployment, but
also the required co-requisite features and expected implementation
effort.
In addition to guidance on the configuration of the Symmetrix
system, this TechBook also provides guidance on which compatibility
features should be added to a deployment to enhance operations and
which other features (such as PAVs) should be employed.

Compatibility 27

Introduction

Enginuity features
While this TechBook does identify specific EMC Enginuity features
implementing the copy-services functionality, the document EMC
Symmetrix VMAX and DMX Series Software Ordering Information and
Configuration Guidelines should be considered the final authority on
feature ordering.
It is not the intention of this TechBook to take any position favoring
the compatibility microcode features versus EMC native Symmetrix
remote copy technologies (SRDF). However, this TechBook draws
attention to the differences when the distinction furthers a greater
understanding of the technologies, their deployment, and solution
configuration.


Introduction

Compatible copy services technologies
The suite of compatibility microcode features comprises remote copy
technologies that have traditionally been identified with IBM and
Hitachi Data Systems (HDS) DASD subsystems. These technologies
constitute a significant portion of the foundational technologies of the
business continuity solutions:
◆ GDPS/PPRC
◆ GDPS/XRC
◆ GDPS/MzGM

Note: GDPS, GDPS/PPRC, GDPS/XRC, and GDPS/MzGM are IBM
trademarks.

This section briefly discusses several variants of GDPS (each
individually licensed) that manage the different remote copy
technologies (PPRC, XRC, FlashCopy, and Global Mirror) and their
implementation over different topologies. Each of these are further
discussed in more detail in this TechBook.

GDPS
GDPS is a suite of licensed software and implementation services
offered by IBM to manage business continuity built on top of and
extending the functionality of native remote copy technology.
Technically, the GDPS offerings are not software products; they are
licensed service offerings of IBM Global Services. Support and
software maintenance is delivered through normal IBM support
channels. See Chapter 2, ”GDPS Business Continuity Solutions,” for
more detailed information.

Compatible Peer This feature provides synchronous and asynchronous volume remote
(PPRC) copy technology between two volumes in different Symmetrix DASD
subsystems (peer-to-peer DASD) see Chapter 3, ”EMC Compatible
Peer (PPRC).”

Compatible Extended This feature provides asynchronous remote copy technology between
(XRC) / Global Mirror two volumes, typically in different Symmetrix DASD subsystems
over extended geographic significant distances. See Chapter 5,
”Compatible Extended (XRC).”

Compatible copy services technologies 29

Introduction

Extended Remote This is a feature that extends the operation and performance of
Copy Enhanced Compatible Extended. It would be considered for most large
Multiple Reader implementations using Compatible Extended. See “Multi-readers” on
page 150.

PPRC/XRC This is a separately licensed feature that enhances the
Incremental Resync disaster-recovery availability of GDPS MzGM three- site solutions by
enabling a quick resynchronization following a planned or
unplanned HyperSwap. See “Three-Site Solution GDPS/MzGM” on
page 203.

Compatible Native This feature provides point-in-time copy technology between two
Flash (FlashCopy) volumes in the same Symmetrix system, see Chapter 8, ”Compatible
Native Flash for Mainframe.”

Compatibility features
The following lists EMC compatibility features with IBM remote copy
features and specific GDPS offering.


Introduction

Valid combinations for compatibility features
Not all copy services features are implemented by the compatibility
microcode features and that affects the combination table.

Table 1 Allowable Compatible Extended copy combinations

If device is
initially --->

Then it can also XRC PPRC FlashCopy
become: XRC Primary Secondary PPRC Primary Secondary Source FlashCopy Target

XRC Primary No, primary Yes, but Yes, this is No Yes, frequently No, missing
cannot be in 2 tmestamps are MzGM configured in timestamps
sessions based on SDM configuration GDPS/XRC
writes

XRC Secondary Yes, but No Yes No Yes No
tmestamps are
based on SDM
writes

PPRC Primary Yes, this is Yes No No, cascaded Yes, but no Yes, but no remote
MzGM PPRC is not remote pair pair FlashCopy
configuration supported on FlashCopy
Symmetrix
systems

PPRC No No No, cascaded No Yes, frequently No
Secondary PPRC is not configured in
supported on GDPS/PPRC
Symmetrix
systems

FlashCopy Yes, frequently Yes, this is Yes, but no Yes, this is Yes Yes, but not on the
Source configured in GDPS/XRC remote pair used in same extents
GDPS/XRC tertiary DASD FlashCopy GDPS/PPRC
for DR testing

FlashCopy No, missing No Yes, but no No Yes, but not on Yes, but not on the
Target tmestamps remote pair the same same extents
FlashCopy extents

Valid combinations for compatibility features 31

Introduction


2
GDPS Business
Continuity Solutions

This chapter provides the following information on GDPS business
continuity solutions:
◆ GDPS overview .................................................................................. 34
◆ GDPS/PPRC ....................................................................................... 35
◆ GDPS/HM .......................................................................................... 37
◆ GDPS/XRC ......................................................................................... 38
◆ GDPS/MzGM..................................................................................... 39
◆ Unsupported GDPS architectures ................................................... 40
◆ Common features of GDPS versions............................................... 41
◆ Documentation ................................................................................... 45

GDPS Business Continuity Solutions 33

GDPS Business Continuity Solutions

GDPS overview
GDPS is a suite of licensed software and implementation services
offered by IBM to manage business continuity built on top of, and
extending, the functionality of, native remote copy technology. There
are several variants of GDPS (each individually licensed) that
manage the different remote copy technologies (PPRC, XRC,
FlashCopy, and Global Mirror) and their implementation over
different topologies.
Technically, the GDPS offerings are not software products. Rather,
they are licensed service offerings of IBM Global Services. However,
support and software maintenance is delivered through normal IBM
support channels.
GDPS implementations are solutions with many deliverables
involving sysplex operations, sysplex definition, z/Series processors
definition, LPAR definition, BCPii configuration, z/OS automation,
inter-site connectivity, and DASD storage. They are
multi-disciplinary implementations undertaken by a team of subject
matter experts, usually under the direction of an experienced
solutions architect who has implemented GDPS previously.
EMC’s role is confined directly to the Symmetrix system: Feature
configuration, remote copy, connectivity, and those GDPS issues
relevant to the implementation and operations of GDPS related to
storage and remote copy.
GDPS is marketed by IBM Global Services as an “open” solution,
meaning it can be implemented on any DASD subsystem that
supports the remote copy features required by the version of GDPS.



GDPS/PPRC
GDPS/PPRC is a business-continuity solution employing
Compatible Peer (PPRC) for volume remote copy. GDPS/PPRC was
the first variant of GDPS and established many of the architectural
components and operations associated with GDPS.
GDPS/PPRC is one of the technologies that implement the
foundational capabilities of FREEZE and HyperSwap.
◆ FREEZE is a process (like an EMC CONGROUP trip) to preserve
the dependent write consistency of the secondary DASD in order
to facilitate the restart of systems, applications, and workloads
using the secondary DASD. GDPS supports both planned and
unplanned FREEZE events to facilitate recovery operations due to
DASD, processor and site failures. FREEZE is an integral part of
GDPS/PPRC, implemented through PPRC’s directive CGROUP
FREEZE operation.
◆ HyperSwap is a process (like EMC AutoSwap™) to transparently
swap device access between DASD units in order to eliminate
DASD subsystems as a single point of failure. GDPS supports
both planned and unplanned HyperSwap to facilitate continuous
operations due to DASD or site failures. HyperSwap also
promotes continuous availability by nearly eliminating system
outage due to planned DASD outages. GDPS/PPRC may or may
not be implemented with a HyperSwap capability.
GDPS/PPRC is tightly bound to its sysplex and seeks to be in the
position of systems and storage control. Consequently,
implementation and control of the remote copy operations and the
systems in the sysplex require:
◆ There is a one-to-one-to-one correspondence of GDPS/PPRC, the
sysplex, and the GDPS/PPRC FREEZE GROUP. All z/OS
systems in the sysplex must be in the same GDPSplex1 and there
is only one write dependency in the sysplex.

1. The operational boundaries of GDPS/PPRC are significantly different
than GDDR. GDPS/PPRC is bound to the sysplex and all systems must be
in a sysplex with GDPS K systems. All systems must be in the same
sysplex. GDPS does not support non-sysplex systems (except for the very
restrictive “foreign system” implementation). In contrast, GDDR is bound
to the CONGROUP and can scale over multiple sysplexes and support
sysplexed systems or non-sysplexed systems.

GDPS/PPRC 35


◆ Operations must avoid z/OS systems HMC management, as well
as PPRC operations performed manually outside of
GDPS/PPRC. System operations must use the GDPS facilities, or
they must be confined to specific operational techniques (even
Stand Alone Dump operations requires a GDPS-specific
methodology to avoid interference with GDPS). SFM policies are
also restricted in a GDPS implementation (system reset is GDPS’s
decision alone).
◆ PPRC DASD defined to GDPS must not be updated by systems
outside the sysplex (or employ a “foreign system” architecture as
outlined in the GPDS/PPRC Installation and Customization Guide).
Data integrity of the FREEZE operation is dependent upon initial
notification being presented to and processed by GDPS/PPRC.

Note: Even read access to PPRC remotely copied DASD is prohibited
since OPEN for READ generates a write to update the VTOC.

◆ Geographic distances are technically limited to sysplex
connectivity and practically limited by application sensitivity1 to
synchronous remote copy.
Depending on the implementation topology and availability
expectations, GDPS/PPRC can resemble either GDDR CONGROUP
or GDDR AutoSwap.
More information is provided in Chapter 3, ”EMC Compatible Peer
(PPRC).”

1. Geographic distance imposes application restrictions for a number of
technical reasons, not limited to remote copy and connectivity.
Applications based on shared data in coupling facilities in multisite
workloads can experience distance limitations more restrictive than
synchronous remote copy and DASD connectivity.



GDPS/HM
GDPS/HyperSwap Manager (GDPS/HM) is a related product to the
more full-function GDPS/PPRC. GDPS/HM lacks the automation of
GDPS/PPRC but provides the basic storage management and
autonomic operations of FREEZE and HyperSwap.
Throughout this document references to GDPS/PPRC are applicable
to GDPS/HM, except where noted.

GDPS/HM 37


GDPS/XRC
GDPS/XRC (Compatible Extended) is a business-continuity solution
for disaster recovery based on XRC. XRC is a long-distance,
asynchronous copy technology with limited performance impact to
the production environment.
GDPS/XRC requires an extensive deployment of z/OS systems and
DASD at the recovery site. GDPS facilitates the operation of DASD
recovery, z/Series system management and restart of production
z/OS systems, applications and workload.
GDPS/XRC has some superficial architectural resemblance to GDDR
SRDF/A in that it is an asynchronous replication solution, but XRC
secondary volumes lack personality-swap capability. GDPS/XRC has
no inherent reverse site switch capability following an unplanned
outage.
GDPS/XRC was the second variant of GDPS introduced.
More information is provided in Chapter 5, ”Compatible Extended
(XRC).”



GDPS/MzGM
GDPS/MzGM is a three-site business-continuity solution combining
high-availability and disaster recovery.
It is built upon a combination of GDPS/PPRC and GDPS/XRC.
GDPS/PPRC manages operations between SITE1 and SITE2.
GDPS/XRC manages operations between the current primary DASD
SITE and SITE3.
GDPS/MzGM offers limited interoperability between the two
component solutions. Interoperation between the GDPS/PPRC and
GDPS/XRC is loosely coupled with few provisions for joint or
coordinated operations.
More information is provided in “Three-Site Solution GDPS/MzGM”
on page 203.

GDPS/MzGM 39


Unsupported GDPS architectures
EMC does not support Global Mirror-based solution GDPS/GM, nor
its three-site implementation, GDPS/MGM.



Common features of GDPS versions
This section contains the following information for common features:
◆ “NetView and system automation for z/OS components” on
page 41
◆ “NetView operator” on page 41
◆ “SCRIPT language with TAKEOVER, CONTROL, and BATCH
scripts” on page 42
◆ “GEOPARM and GEOXPARM storage policy definitions” on
page 43
◆ “Policy Data Base (PDB)” on page 43
◆ “Sysplex” on page 43
◆ “K systems” on page 44

NetView and system automation for z/OS components
GDPS runs in NetView address space and employs NetView and
System Display Facility (SDF) panels for the operator interface,
variable management, automated operations, DASD remote copy
relationships, and inter system connectivity. GDPS is an application
within NetView, which makes use of many of the imbedded
technologies and automated operations capabilities of NetView.
GDPS employs System Automation for z/OS (also known as “SA”)
for definition of the computing architecture, the business availability
and recovery policies, host systems and coupling facility definitions,
BCPii interface, recovery scripts, as well as maintenance of the
interface to manage the definitions saved in the Production Data Base
(PDB).

NetView operator
Netview operator provides the human interface to GDPS (also
available through a web interface).
◆ Top-down DASD remote copy panels with display, status, and
manual operations
◆ Site and remote copy status
◆ Sysplex and systems management

Common features of GDPS versions 41


◆ Execution of control scripts
◆ Activation of new PPRC definitions and GEOPLEX policy
◆ Access to system automation’s SDF for dynamic monitoring and
warning

SCRIPT language with TAKEOVER, CONTROL, and BATCH scripts
GDPS scripts1 consist of GDPS keywords that execute in the
NetView Address space2. There are three kinds of scripts. The real
distinction is when and how they can be invoked.
◆ TAKEOVER scripts are run as a result of unplanned events, such
as DASD failure, remote copy linkage failure, system failure, and
site failure. Also known as unplanned actions, they cannot be
invoked by manual operations (although there are known
activities that can precipitate the failure symptoms and invoke the
scripts). It is unlikely that EMC personnel would be involved
with TAKEOVER script creation and or maintenance.
TAKEOVER script names are generally reserved names that
identify the failure or component.
◆ CONTROL scripts are run by a NetView operator as a result of
selecting the CONTROL script for execution. EMC involvement
with implementation and testing of CONTROL scripts is possible.
◆ BATCH scripts resemble CONTROL scripts, but can be invoked
externally to the GDPS NetView operator.
GDPS scripts are unique to every GDPS implementation. The scripts
are very specific to the individual product, with few examples of
scripts that can be run in every environment.
This TechBook describes some operational aspects and documents
the GDPS SCRIPT keywords. Documentation of creation,
management, and activation of the SCRIPTs, which requires using the
SA for z/OS ISPF interface, is beyond the scope of this manual.

1. GDPS scripts are significantly different in form and operation from GDDR
scripts.
2. GDPS scripts are not REXX scripts, although there are keywords to
invoke external REXX operations.



GEOPARM and GEOXPARM storage policy definitions
GEOPARM specifications establish the remote copy relationships
between volumes (PPRC, XRC, and FlashCopy). PPRC GEOPARM
establishes the expected linkage definitions and FREEZE GROUP
definitions. XRC GEOXPARM defines to GDPS the expected SDM
architecture. GEOPARM syntax is very dependent on the type of
GDPS employed. Component specification, volume inclusion, and
the definition of volume remote copy relationships establish the
GDPS policy of the limit of operations and operational awareness.
Basically, the GEOPARM is a PDS with one active member allocated
to the NetView domain1 (started task) running GDPS and edited
through ISPF.
Alteration of GDPS’s mirroring definitions requires that you first
alter the GEOPARM definitions, followed by validation and
activation of the new GEOPARM.

Policy Data Base (PDB)
GEOPLEX policy is defined in SA for z/OS Policy Database. The
operational policies of GDPS are established in the PDB, and the
available settings are very dependent on the deployed version of
GDPS. For instance, the FREEZE and SWAP policies of GDPS/PPRC
are established in GDPS/PPRC PDB. Creation of the GDPS policy
requires extensive customization of the standard sections of the PDB,
as well as the addition of User ET pairs2. GDPS SCRIPTs also reside in
the PDB as keyword pairs.

Sysplex
GDPS employs sysplex functionality and must be implemented as a
sysplex. The one notable exception is GDPS/GM, which employs
Global Mirroring, employs limited sysplex functionality, and is not
supported by EMC’s compatibility features. GDPS/PPRC is an

1. It is not uncommon to encounter environments with NetView domains
dedicated to operations other than GDPS; only the GDPS NetView has a
GEOPARM DD statement.
2. In form and structure, the PDB somewhat resembles the registry of
Windows: Keywords and values.

Common features of GDPS versions 43


integral part of the production sysplex. GDPS/XRC runs a distinct
recovery sysplex dedicated to running GDPS at the remote disaster
recovery (DR) site.

K systems
A required feature of GDPS solutions are GDPS K1 z/OS systems
(like GDDR C systems), which provide operational control. They
should be designed with sufficient redundancy and separation to
provide a point of control independent of DASD, processor, or site
failures.
The GDPS K systems have specific Symmetrix implementation
requirements, Principally, K system connectivity and K system
isolation are important deliverables of EMC in a GDPS deployment.

1. GDPS was developed for VPC (now Euroclear Sweden) in Stockholm
Sweden. Throughout the GDPS code, panel names, and global variables,
there are legacy references to the initial site and its Swedish origin. The K,
for KONTROL, is one of these legacies.



Documentation
This section provides documentation references.

Advanced Copy Services
The DFSMS Advanced Copy Services manual documents XRC,
FlashCopy, PPRC operations, TSO commands, batch interfaces,
diagnostic system commands, and assembler interfaces.
The EMC suite of compatible Advanced Copy Services is externally
compliant with the documentation. EMC does not provide separate
user guides for these features.

GDPS manuals
Generalized information regarding GDPS is available in GDPS Family
– An Introduction to Concepts and Capabilities, which is available for
download. Detailed implementation, customization, and operations
material is available in the individual offering installation and
customization guides, which are licensed IBM materials.

Documentation 45

3
EMC Compatible Peer
(PPRC)

This chapter provides the following information on EMC Compatible
Peer (PPRC):
◆ PPRC overview................................................................................... 48
◆ PPRC components.............................................................................. 49
◆ SRDF/S operations and Compatible Peer...................................... 51
◆ Supported and non-supported PPRC modes ................................ 52
◆ PPRC operation .................................................................................. 53
◆ Supported PPRC features ................................................................. 57
◆ PPRC TSO commands ....................................................................... 68
◆ Other PPRC interfaces ....................................................................... 69
◆ Compatible Peer versus SRDF/S and Adaptive Copy ................. 70
◆ FAST and Compatible Peer............................................................... 70
◆ Compatible Peer limitations ............................................................. 70
◆ Designing the solution for z/OS...................................................... 71
◆ Conversion from SRDF/S to PPRC emulation .............................. 74

EMC Compatible Peer (PPRC) 47

EMC Compatible Peer (PPRC)

PPRC overview
Compatible Peer (PPRC) is a volume-to-volume physical remote copy
feature between different Symmetrix DASD subsystems. The EMC
official name for this feature is Compatible Peer.
◆ Externally, it is somewhat analogous to SRDF/S and Adaptive
Copy1, and there is some overlap in their operational modes.
◆ Internally, Compatible Peer Remote Copy employs SRDF/S and
Adaptive Copy2 operations and physical components in a
manner of operation compatible with PPRC.
Because microcode operation shares some of the same components as
SRDF, but is managed as PPRC, it is sometimes referred to as PPRC
emulation.
EMC Compatible Peer is operationally equivalent to PPRC in a
GDPS/PPRC implementation and most native PPRC
implementations. When enabled with the compatible PPRC feature,
EMC Symmetrix subsystems respond to PPRC CCWs, report errors,
as PPRC would, and can be managed through the external interfaces
of TSO commands, ICKDSF directives, and the Advanced Copy
Services API. This enables manual management or automated
management (GDPS/PPRC or GDPS/HM) of PPRC operations on a
Symmetrix system.
Compatible Peer’s volume pairs must be composed of EMC volumes.
However, Symmetrix systems with Compatible Peer can be
configured with other vendor DASD subsystems employing PPRC
(side-by-side).
Even though Compatible Peer employs SRDF/S microcode
operations and physical Symmetrix components, it is operated
entirely by PPRC directives. Compatible Peer requires no EMC
software for its definition and operation; in fact, the Symmetrix
Control Facility address space (SCF) is counter-indicated in many
GDPS/PPRC implementations.

1. Compatible Peer employs SRDF/S and Adaptive Copy operations and
components for remote copy operations. PPRC Primary Volumes and
PPRC Secondary Volumes are SRDF/S R1 and R2 devices. It also uses the
RDF linkage between a Symmetrix system and internally employed by
SRDF Device Groups.
2. Operation of PPRC volumes by SRDF commands is not supported.



PPRC components
Figure 1 illustrates the components of Compatible Peer implemented
in a Symmetrix system.

Figure 1 PPRC components

Major PPRC components, as shown in Figure 1, include:
1. z/OS system PPRC links, devices, and remote copy are defined
and managed from z/OS PPRC directives exclusively.
2. PRIMARY Symmetrix DASD subsystem.
a. Symmetrix Primary DASD serial number required for PPRC
directives.

PPRC components 49


b. Compatible Peer licensing.
c. PRIMARY DASD device addresses required for PPRC
directives.
d. LCUs and SSIDs required for PPRC directives. The LCU and
SSID have roles in the definition of the logical PPRC paths as
well as identifying the device-to-device remote copy
relationships.
e. SRDF GROUP (in the range 00-3F), defined in the Symmetrix
configuration, is required for PPRC directives.
3. SECONDARY Symmetrix DASD subsystem.
a. Symmetrix Secondary DASD serial number required for PPRC
directives.
b. Compatible Peer licensing.
c. SECONDARY DASD device addresses required for PPRC
directives.
d. LCUs and SSIDs required for PPRC directives.
e. SRDF GROUP (in the range 00-3F), defined in the Symmetrix
configuration, is required for PPRC directives (although the
SRDF GROUP on the secondary VMAX is not required to be
the same as the SRDF GROUP on the primary VMAX, it
typically is).
4. FICON channel connectivity.
a. FICON channel connectivity to Primary DASD.
b. FICON channel connectivity to Secondary DASD.
5. SRDF linkage.
a. VMAX-to-VMAX physical links are used to define the
LCU-to-LCU logical PATHs.
b. Physical RDF linkage (up to 8 shared physical RDF links per
PPRC logical PATH between LCUs).



SRDF/S operations and Compatible Peer
IMPORTANT
The Symmetrix configuration file and physical connectivity must
be in agreement for Compatible Peer to emulate PPRC predictably,
especially in GDPS/PPRC implementations.

Compatible Peer actually employs components and some microcode
operations of SRDF/S. Compatible Peer’s PPRC PATHs, PPRC
volume pairs, and CGROUPs operate exactly as PPRC PATHs,
volume pairs, and CGROUPs.
The logical entity of SRDF/S GROUP name defined in the Symmetrix
configuration file and the physical SRDF links are two components
that are externalized in Compatible Peer definition and operation.

External manifestation of the SRDF/S GROUP name
◆ The SRDF/S GROUP Name defined in the Symmetrix
configuration file is represented in the PPRC PATH LINK
definition between LCUs.
◆ Typically, multiple SRDF/S GROUP Names are created in the
Symmetrix configuration file. PPRC paths can all employ the
same SRDF/S GROUP name or use different ones. With PPRC,
preservation of the dependent writes is formed by some external
entity using CGROUP FREEZE/RUN technology, such as
GDPS/PPRC. Therefore, it is immaterial if different SRDF/S
GROUP names are used or the same one.
◆ Except for its role in the definition of PPRC PATHs, the SRDF/S
GROUP Name is not involved in the formation of consistency or
the external operation of Compatible Peer.
◆ Symmetrix configuration file definition for RDF_Directors and
the RDF_GROUPs should be in agreement with the intended
LINK definitions in the PPRC CESTPATH definitions.
◆ Because the underlying technology is SRDF, successful PPRC
logical PATH management (through CESTPATH, CDELPATH,
abd CGROUP FREEZE) depend upon agreement between the
Symmetrix configuration file definition and CESTPATH
definitions (and GDPS GEOPARM specification of the links
between SSIDs in the LINKs Section).

SRDF/S operations and Compatible Peer 51


Supported and non-supported PPRC modes
Compatible Peer supports two modes of PPRC operations:
◆ Metro Mirror is a synchronous remote copy between volume
pairs using PPRC PATHs over physical links. Additionally, it is
capable of forming dependent write consistency.
◆ Global Copy, or PPRC XD, is a non synchronous copy of changed
tracks, without regard for consistency and without a CGROUP. It
is primarily used for copying data when dependent write
consistency can be externally accomplished. Also, it is used by
GDPS as a performance feature during resynchronization
operations, when consistency is unattainable. PPRC XD is similar
in operation to SRDF Adaptive Copy Disk Mode.
The following modes of PPRC operation are not supported by
Compatible Peer:
◆ Global Mirror (GM): A combination of PPRC XD, FlashCopy and
remote control by a designed control DASD subsystem.
◆ Metro Global Mirror (MGM): A cascaded configuration of Metro
Mirror and Global Mirror to create a three- site solution.


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